From 5fb0b2c190d0f4ae3c6de9019834fb748df0f59e Mon Sep 17 00:00:00 2001 From: Ani Date: Thu, 21 Oct 2021 16:20:10 +0100 Subject: [PATCH] stb_truetype: Update from 1.25 to 1.26 --- 3rdparty/stblib/include/stb_truetype.h | 102 ++++++++++++++++++++----- 1 file changed, 81 insertions(+), 21 deletions(-) diff --git a/3rdparty/stblib/include/stb_truetype.h b/3rdparty/stblib/include/stb_truetype.h index 9414a63412..bbf2284b16 100644 --- a/3rdparty/stblib/include/stb_truetype.h +++ b/3rdparty/stblib/include/stb_truetype.h @@ -1,4 +1,4 @@ -// stb_truetype.h - v1.25 - public domain +// stb_truetype.h - v1.26 - public domain // authored from 2009-2021 by Sean Barrett / RAD Game Tools // // ======================================================================= @@ -58,6 +58,7 @@ // // VERSION HISTORY // +// 1.26 (2021-08-28) fix broken rasterizer // 1.25 (2021-07-11) many fixes // 1.24 (2020-02-05) fix warning // 1.23 (2020-02-02) query SVG data for glyphs; query whole kerning table (but only kern not GPOS) @@ -271,8 +272,8 @@ //// SAMPLE PROGRAMS //// // -// Incomplete text-in-3d-api example, which draws quads properly aligned to be lossless -// +// Incomplete text-in-3d-api example, which draws quads properly aligned to be lossless. +// See "tests/truetype_demo_win32.c" for a complete version. #if 0 #define STB_TRUETYPE_IMPLEMENTATION // force following include to generate implementation #include "stb_truetype.h" @@ -307,10 +308,10 @@ void my_stbtt_print(float x, float y, char *text) if (*text >= 32 && *text < 128) { stbtt_aligned_quad q; stbtt_GetBakedQuad(cdata, 512,512, *text-32, &x,&y,&q,1);//1=opengl & d3d10+,0=d3d9 - glTexCoord2f(q.s0,q.t1); glVertex2f(q.x0,q.y0); - glTexCoord2f(q.s1,q.t1); glVertex2f(q.x1,q.y0); - glTexCoord2f(q.s1,q.t0); glVertex2f(q.x1,q.y1); - glTexCoord2f(q.s0,q.t0); glVertex2f(q.x0,q.y1); + glTexCoord2f(q.s0,q.t0); glVertex2f(q.x0,q.y0); + glTexCoord2f(q.s1,q.t0); glVertex2f(q.x1,q.y0); + glTexCoord2f(q.s1,q.t1); glVertex2f(q.x1,q.y1); + glTexCoord2f(q.s0,q.t1); glVertex2f(q.x0,q.y1); } ++text; } @@ -3061,6 +3062,23 @@ static void stbtt__handle_clipped_edge(float *scanline, int x, stbtt__active_edg } } +static float stbtt__sized_trapezoid_area(float height, float top_width, float bottom_width) +{ + STBTT_assert(top_width >= 0); + STBTT_assert(bottom_width >= 0); + return (top_width + bottom_width) / 2.0f * height; +} + +static float stbtt__position_trapezoid_area(float height, float tx0, float tx1, float bx0, float bx1) +{ + return stbtt__sized_trapezoid_area(height, tx1 - tx0, bx1 - bx0); +} + +static float stbtt__sized_triangle_area(float height, float width) +{ + return height * width / 2; +} + static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill, int len, stbtt__active_edge *e, float y_top) { float y_bottom = y_top+1; @@ -3115,10 +3133,10 @@ static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill, float height; // simple case, only spans one pixel int x = (int) x_top; - height = sy1 - sy0; + height = (sy1 - sy0) * e->direction; STBTT_assert(x >= 0 && x < len); - scanline[x] += e->direction * (1-((x_top - x) + (x_bottom-x))/2) * height; - scanline_fill[x] += e->direction * height; // everything right of this pixel is filled + scanline[x] += stbtt__position_trapezoid_area(height, x_top, x+1.0f, x_bottom, x+1.0f); + scanline_fill[x] += height; // everything right of this pixel is filled } else { int x,x1,x2; float y_crossing, y_final, step, sign, area; @@ -3134,40 +3152,79 @@ static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill, dy = -dy; t = x0, x0 = xb, xb = t; } - assert(dy >= 0); - assert(dx >= 0); + STBTT_assert(dy >= 0); + STBTT_assert(dx >= 0); x1 = (int) x_top; x2 = (int) x_bottom; // compute intersection with y axis at x1+1 - y_crossing = (x1+1 - x0) * dy + y_top; + y_crossing = y_top + dy * (x1+1 - x0); + + // compute intersection with y axis at x2 + y_final = y_top + dy * (x2 - x0); + + // x1 x_top x2 x_bottom + // y_top +------|-----+------------+------------+--------|---+------------+ + // | | | | | | + // | | | | | | + // sy0 | Txxxxx|............|............|............|............| + // y_crossing | *xxxxx.......|............|............|............| + // | | xxxxx..|............|............|............| + // | | /- xx*xxxx........|............|............| + // | | dy < | xxxxxx..|............|............| + // y_final | | \- | xx*xxx.........|............| + // sy1 | | | | xxxxxB...|............| + // | | | | | | + // | | | | | | + // y_bottom +------------+------------+------------+------------+------------+ + // + // goal is to measure the area covered by '.' in each pixel + // if x2 is right at the right edge of x1, y_crossing can blow up, github #1057 + // @TODO: maybe test against sy1 rather than y_bottom? if (y_crossing > y_bottom) y_crossing = y_bottom; sign = e->direction; - // area of the rectangle covered from y0..y_crossing + + // area of the rectangle covered from sy0..y_crossing area = sign * (y_crossing-sy0); - // area of the triangle (x_top,y0), (x+1,y0), (x+1,y_crossing) - scanline[x1] += area * (x1+1 - x_top)/2; + + // area of the triangle (x_top,sy0), (x1+1,sy0), (x1+1,y_crossing) + scanline[x1] += stbtt__sized_triangle_area(area, x1+1 - x_top); // check if final y_crossing is blown up; no test case for this - y_final = y_crossing + dy * (x2 - (x1+1)); // advance y by number of steps taken below if (y_final > y_bottom) { y_final = y_bottom; dy = (y_final - y_crossing ) / (x2 - (x1+1)); // if denom=0, y_final = y_crossing, so y_final <= y_bottom } - step = sign * dy * 1; // dy is dy/dx, change in y for every 1 change in x, which is also how much pixel area changes for each step in x + // in second pixel, area covered by line segment found in first pixel + // is always a rectangle 1 wide * the height of that line segment; this + // is exactly what the variable 'area' stores. it also gets a contribution + // from the line segment within it. the THIRD pixel will get the first + // pixel's rectangle contribution, the second pixel's rectangle contribution, + // and its own contribution. the 'own contribution' is the same in every pixel except + // the leftmost and rightmost, a trapezoid that slides down in each pixel. + // the second pixel's contribution to the third pixel will be the + // rectangle 1 wide times the height change in the second pixel, which is dy. + + step = sign * dy * 1; // dy is dy/dx, change in y for every 1 change in x, + // which multiplied by 1-pixel-width is how much pixel area changes for each step in x + // so the area advances by 'step' every time + for (x = x1+1; x < x2; ++x) { - scanline[x] += area + step/2; // area of parallelogram is step/2 + scanline[x] += area + step/2; // area of trapezoid is 1*step/2 area += step; } STBTT_assert(STBTT_fabs(area) <= 1.01f); // accumulated error from area += step unless we round step down + STBTT_assert(sy1 > y_final-0.01f); - // area of the triangle (x2,y_crossing), (x_bottom,y1), (x2,y1) - scanline[x2] += area + sign * (x_bottom - x2)/2 * (sy1-y_crossing); + // area covered in the last pixel is the rectangle from all the pixels to the left, + // plus the trapezoid filled by the line segment in this pixel all the way to the right edge + scanline[x2] += area + sign * stbtt__position_trapezoid_area(sy1-y_final, (float) x2, x2+1.0f, x_bottom, x2+1.0f); + // the rest of the line is filled based on the total height of the line segment in this pixel scanline_fill[x2] += sign * (sy1-sy0); } } else { @@ -3175,6 +3232,9 @@ static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill, // clipping logic. since this does not match the intended use // of this library, we use a different, very slow brute // force implementation + // note though that this does happen some of the time because + // x_top and x_bottom can be extrapolated at the top & bottom of + // the shape and actually lie outside the bounding box int x; for (x=0; x < len; ++x) { // cases: